1. Field of the Invention
The present invention relates to a printing system, a method of generating a halftone processing rule, a method of acquiring a characteristic parameter, image processing device and method, a halftone processing rule, a halftone image, a printed material manufacturing method, an inkjet printing system, and a program, and more particularly, to an image processing technology of generating a print halftone image from a continuous-tone image.
2. Description of the Related Art
In a printing system in which a printing device such as an ink jet printing device or an offset printing device forms an image, a halftone process is performed on data of a continuous-tone image expressed by multiple gradations, and thus, data of a halftone image corresponding to an image output mode of the printing device is generated. The data of the halftone image is used as printing dot image data indicating a dot pattern in which dot arrangement of halftone dots reproduced by the printing device or a size of each dot is defined. The printing device forms an image based on the data of the halftone image.
As the method of the halftone process, there are various methods such as a dither method, an error diffusion method, and a direct binary search (DBS) method. For example, in the dither method, multi-value data of the continuous-tone image is converted into binary dot data by comparing a threshold value and a pixel value of a processing target pixel using a threshold value matrix called a dither mask, assigning dot-ON pixels in a case where the pixel value is equal to or greater than the threshold value and assigning dot-OFF pixels in a case where the pixel value is less than the threshold value.
JP2012-222433A describes a printing system capable of selecting a halftone process appropriate for a printed material in consideration of productivity of the printed material. The printing system described in JP2012-222433A may select one signal processing condition from signal processing conditions of a plurality of halftone processes having different dot distribution characteristics, and may perform the halftone process using the selected signal processing condition.
In the printing system described in JP2012-222433A, four printing mode may be prepared, and an operator may select the printing mode. If the printing mode is selected, since a recommended halftone processing condition is presented, the operator can select an optimum halftone processing condition.
“Digital Halftoning Techniques for Printing” (Thrasvoulos N. Papas IS&T's 47Th Annual Conference, Rochester, N.Y., May 15-20, 1994), “Model-Based Digital Halftoning” (Thrasvoulos N. Papas, Jan P. Allebach, and David L. Neuhoff, IEEE SIGNAL PROCESSING MAGAZINE July 2003, p 14-27), and “Inkjet Printer Model-Based Halftoning” (Je-Ho Lee and Jan P. Allebach, IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 14. NO. 5 May 2005, P 674-689) describe a technology called model-based halftoning. “Digital Halftoning Techniques for Printing” (Thrasvoulos N. Papas IS&T's 47Th Annual Conference, Rochester, N.Y., May 15-20, 1994), describes a method of performing halftone design capable of improving dispersibility of a dot having an intermediate gradation based on an image in which the overlapping of dots is reproduced in consideration of the spreading of a dot and the size of a dot at the time of printing from the characteristics of the printing system. The term of “halftone design” means that the specific content of the halftone process is designed, that is, the halftone processing rule is generated.
“Model-Based Digital Halftoning” (Thrasvoulos N. Papas, Jan P. Allebach, and David L. Neuhoff, IEEE SIGNAL PROCESSING MAGAZINE July 2003, p 14-27), and “Inkjet Printer Model-Based Halftoning” (Je-Ho Lee and Jan P. Allebach, IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 14. NO. 5 May 2005, P 674-689) describe a method of performing halftone design based on an image in which bidirectional error characteristics as position shift characteristics which is a position shift of a dot in an outward path and an inward path through a reciprocating operation in serial scanning are reproduced in addition to taking account of the overlapping of the dots.
JP2013-038643A describes a method of performing halftone design having tolerance to a paper transport error or bidirectional error in a serial scanning type. JP2009-018479A describes a method of performing halftone design having tolerance to a position shift of a printing head in a line printer including a line head configured such that a plurality of printing head is arranged.
JP2013-038643A describes a multipath and JP2009-018479A describes a single path, and these literatures describe that the halftone design capable of improving the dispersibility of a dot on a per path basis is performed. These literatures may be classified as a “path dispersion halftoning” technology.